If it is a nock height issue, it will show up with bare shafts/broadheads. If you shoot split finger, it may be a nock pinch issue. Try a tab with a finger seperator, or just a different tab or glove altogether, or altering your finger pressure on the sting. Also, if the base of your feathers are too sharp, or too thick, they will cause rest wear. Try a different brand of feather, or re-finish them yourself. Or it could be caused by a spine issue. This would also show up in a bare shaft/broadhead test.